Carburetor accelerating means



'May 7, 1940. E, OLSON 2,199,509

CARBURETOR ACCEL'ERATING MEANS Filed Oct. 22, 1957 lNvENToR [LMf/P OLso/v.

. ATTORNEY. 'i

Patented May 7, 1940 UNITED STATES 2,199,509 CARBURETOR ACCELEBATING MEANS 'Elmer 0mm, Detroit, Mich., signor to M. E.

Chandler, Detroit, Mich;

Application october zz, 1931, serial Ng. 170,459

1 Claim.

'This invention relates to means for supplying time when the carburetor is adjusted to function the quantityof fuel needed for acceleration, and specicalLv it relates to that type of accelerating means which includes a fuel pump operatedv by. a throttle valve. One difliculty that has been experiencedwith accelerating means of this type is that they'continue to function after the need for extra fuel during acceleration has ended. This results in awaste of fuel. In order to counlll teract this waste of fuel, heavily loaded check valves are used which are only unseated by the sudden opening of the throttle. In order words, a.

positive pressure is required to force the vfuel into the carburetor during acceleration. In order l5 to accomplish this result, the valves are either heavy or else they are .spring loaded. In either event, the valve seat is quickly damaged and a leaky,valve seat results, which, of course, will discharge during a period when the accelerating means are intended to be inoperative.

The specific object of this invention,.therefore, is to reduce the load on the shut off valve and at the same time, prevent this premature discharge of the fuel pump and this improved result is accomplished by utilizing the depression in the air entrance of a carburetor for positively holding the valve on its seat, so that as the engine speeds up, the valve is seated by the suction and thus a relatively light valve can be used. It is to be 80 understood that at low engine speed with wide open throttle, there is no tendency for the fuel pump outlet to discharge prematurely because under this condition there is no depression in the air entrance, but when the engine is going at top 85 speed, with wide open throttle, it is very possible to have a considerable depression in the air entrance due partly to velocity and partly to the air cleaner which is normally placed on the air entrance. This restriction means quite a few inches 40 of water and of course would cause a large quantity of fuel to pass through the accelerating pump in Kthe event that there was any leak in the seat of the shut oil valve.

In the figures: 4,5 Figure 1 shows a cross sectional elevation showing all the elements of my invention.

Figure 2 shows a modification of the novel feature of my invention.

Figure 3 shows a second modification. 50 Figure 4 shows a third'modiflcation.

In the figures, I0 indicates the air entrance; Il is the choke valve located therein, which is of the well known type, but has no bearing on this invention except that when it is partly closed, it 55 would cause the fuel pump outlet to operate at a without the discharge from the fuel pump. The air flows past the choke valve to the venturi 26. In the throat 'of this venturi is located a fuel nozzle 39 which 1is provided with a shoulder l5. 5 This shoulder, by reason of its location within the throat of the venturi 21, induces the fuel to flow up the passage I1 across the horizontal passage l5. By this means, the fuel flows from the oat chamber l2 through the restrictionk I8 which is l0 the master metering nozzleof the carburetor.

The fuel level in the oat chamber I2 is maintained on a constant level by means of the iioat i3 and by means of oat mechanism which is not shown. The fuel discharge from the fuel`outlet I6 is atomized by air admitted through small air orifices I9 forming an emulsion. The fuel for low speed is obtained from this emulsion and is drawn off through the horizontal passage down the inclined passage 2l and discharges into 20 the mixture outlet 56 through the low speed valve outlets 22 and 23. These outlets are located' one above and one below the throttle valve 24 which is mounted on the throttle valve shaft 25. The orifice 23 is adjusted by a needle valve to take 25 care of slight differences between engines and for other reasons. This particular form of low speed is of a well known type and forms no part of this invention.

The throttle shaft is operated by the throttle 30 lever and is connected through another lever 46 to the link 41 to an L-shaped link 48. This v link 48 is guided in the main body of the float chamber casting and engages with a shoulder 5| on the end of a piston 50. The piston is slid- 35 able through the link 49 and the head 5I engages with the link 46 by reason of the compression of the spring 49. The piston 50 is sealed by 'means of a cylinder ring 55.l A spring 51 inside the piston 50 engages with a loose pin 56. When the pump piston 50 descends, the pin 56 strikes the bottom wall of the cylinder 52 and the spring 51 is thereafter compressed so that the pumping effect of the piston 50 is delayed and the discharge of the fuel occupies an appreciable period of time. This 45 is' the follow up pump principle which is the subject of my co-pending patent application Serial No. 81,696, filed May 25, 1936. The fuellows through the passage 54 from the float chamber l2 into the cylinder 52 past the check valve 53. 50 Fuel is discharged from the cylinder .52 through the passage 58 past the check valve 59 and discharges into the mixing chamber through the passage 60.

All the parts so farmentioned belong to the 55 prior art. The improvement which I have made results from the addition of the following parts. The ball 6l is arranged to rest on the valve 59.

Suction is applied to the lower side of this ball 59 is iirmly pressed on its seat. I have further discovered that I can substitute aluminum for brass for this needle valve 59 and the light weight valve does not damage the seat as quickly as a heavier valve will, but the light weight valve is just aseiective for the reason that the pressure of the atmosphere acting on the ball Si is a substitute 'for the weight of a heavy brass needle 53. l

In place' of the rather bulky Valve 59 in Fig. 1, I can substitute in Fig, 2 a rather smaller valve 59 and make it of brass and increase the Weight by means of the piston 68 which is made integral with the valve 59. Again the atmospheric pressure is applied through the opening 63 to the opening 62 and through the opening in the center of the cylinder 69 in which the piston 68 reciprocates.

In Figure 3 there is a slightly diierent solution. In this -the cylinder valve 59 is cut down in weight by being shortened. A loose piece 'l0 is supported on a spring 'Il and acts as a cushion so that when the valve 59 is raisedfrom its seat, the spring 1I is compressed. A set screw l2 is arranged to.1imit the travel of the spring supported weight 1D. By this means the exact opening of the valve 59 can he limited. When the car is riding on a rough road, instead of the full weight of the valve 59 pounding on the seat every time the car hits a bump, the Weight of the valve is partially spring supported and oi course, that portion of the valve supported by the spring 1l, that is to say, the portion 10. does not damage the valve seat as rapidly as would be the case if the valve were made all in one piece.

In Figure 4 the principle of operation is more similar to that shown in Figures 1 and 2. A diaphragm 85 takes the place of the piston 68 in Figure 2. 'Ihisdiaphragm connected tothe valve 5S. On the lower side it is subjected to the depression existing in the entrance to the venturi 26. 0n its upper side it is subjected to atmospheric pressure admitted through the opening 6l. A spring 68 supplies the necessary pressure to prevent theV valve leaking. Y

What I claim is: In a carburetor having an air entrance, a mixing chamber, a mixture outlet, a throttle valve therein, an accelerating fuel pump, a fuel outlet therefrom discharging into the air entrance of the carburetor, a. two part check valve in said fuel outlet, the lower portion being adapted to close the outlet, the upper portion being adapted to engage with the lower portion and to act as a piston responsive on the lower side to the suction in the air entrance on the atmospheric side of the throttle valve, and on its upper side to atmospheric pressure whereby the atmospheric pressure is adapted to supplement the weight of the lower portion of the check valve in order to overcome the effect of the suction in the all' entrance. I v

v ELMER oLsoN. 

